JPH0914316A - Coil spring for lateral deformation prevention - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a coil spring designed to prevent lateral deformation. [Structure] In the cylindrical coil spring 1, the cross-sectional area of the wire at the center is smaller than the cross-sectional area of the wire at both ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil spring which is resistant to lateral deformation under a compressive load.

[0002]

2. Description of the Related Art Compression coil springs are widely used because they are relatively inexpensive to manufacture, compact and highly efficient.
Cylindrical coil springs are often used because they are easy to manufacture,
There are also several variants depending on the application. An unequal pitch coil spring is one in which the coil pitch is made denser near one end, or made coarser from one end toward the other end, and coil adhesion occurs as the load increases, which is effective. The number of turns is reduced and the spring constant is increased. Also,
Coil springs that change the wire diameter are also used to obtain non-linear characteristics. In this case, a method of reducing the wire diameter at both ends is used.

[0003]

When the height of the coil spring is higher than the coil diameter to some extent, the coil spring causes buckling and lateral displacement (displacement in a direction perpendicular to the height) occurs. This buckling is likely to occur depending on the supporting conditions at both ends, is less likely to occur when fixing both ends, and is likely to occur when rotating both ends. When such lateral deformation occurs, the resistance to the expansion and contraction of the spring increases, and it also comes into contact with the device incorporating the spring to restrain the operation of the device. In particular, when used in outer space, the coefficient of friction becomes large in a vacuum, and there is a case in which a material that comes into contact with the surface becomes stuck or gets caught. It should be noted that, on the ground, if a spring is coated with a lubricant such as oil or moly coat, it is possible to prevent the resistance of the spring from increasing or sticking. However, such a thing cannot be used in space to prevent pollution.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a coil spring which prevents lateral deformation.

[0005]

In order to achieve the above object, in the invention of claim 1, the cylindrical wire spring has a central wire cross-sectional area smaller than both end wire cross-sectional areas.

According to the second aspect of the invention, in the cylindrical coil spring, the coil pitch at the center is smaller than the coil pitch at both ends.

[0007]

According to the invention of claim 1, in the cylindrical coil spring, the cross-sectional area of the wire in the central portion is smaller than the cross-sectional area of the wire in both ends. Therefore, when the load applied to the spring increases, the wire in the central portion of the spring increases. Areas with a small line cross-sectional area come into close contact with each other. As a result, the rigidity of the central portion is increased, buckling is less likely to occur, and lateral deformation is less likely to occur.

In the invention of claim 2, since the coil pitch of the central portion of the cylindrical coil spring is smaller than the coil pitch of both ends, when the load applied to the spring is increased, the pitch of the central portion of the spring is small. It adheres prior to. As a result, the rigidity of the central portion is increased, buckling is less likely to occur, and lateral deformation is less likely to occur.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cylindrical coil spring of the first embodiment, (A) is a longitudinal sectional view, and (B) is a diameter of a wire. The cylindrical coil spring 1 is composed of an element wire 2 having a circular cross section, and the element wire diameter d1 at the center of the cylindrical coil spring 1 is smaller than the element wire diameter d2 on the end side. This ratio d1 / d2 is the coil height H
And the coil diameter D, the aspect ratio H / D, and the fixing conditions at both ends of the cylindrical coil spring 1 are determined.

FIG. 2 is a spring characteristic diagram showing the compressive load applied in the height direction of the cylindrical coil spring 1 and the amount of contraction in the height direction. When the compressive load increases, the central part starts to adhere at Ps. Ps
Until then, the load and contraction amount are linear, but become non-linear when the contact between the central coils starts. When the close contact is completed at Pf, only the coils at both ends are compressed, and the central parts are closely contacted to increase the rigidity and suppress the occurrence of buckling and prevent lateral deformation.

FIG. 3 shows a side view of the cylindrical coil spring of the second embodiment. Cylindrical coil springs have the same wire diameter,
The pitch p1 at the central portion is smaller than the pitch p2 at both ends. This ratio p1 / p2 is the coil height H and the coil diameter D.
And the aspect ratio H / D and the fixing conditions at both ends of the cylindrical coil spring 1 are taken into consideration. FIG. 2 is applied as it is to the spring characteristic diagram. When the compressive load increases, the close contact starts at Ps with the coil having a dense central pitch. The load and the contraction amount are linear up to Ps, but become nonlinear when the contact between the central coils starts. When the close contact of the coils is completed at Pf, only the coils having large pitches at both ends are compressed, and the central parts are in close contact with each other to increase rigidity and suppress buckling and prevent lateral deformation.

[0012]

As is apparent from the above description, in the present invention, the diameter of the wire of the cylindrical coil is made smaller in the central portion than in the both end portions. The rigidity is increased to prevent buckling and lateral deformation. Further, since the pitch of the cylindrical coil is made smaller at the central portion than at the both end portions, the coils are first brought into close contact with each other at the central portion during compression, the rigidity of the central portion is increased, and buckling can be prevented to prevent lateral deformation. As a result, even if a device or the like incorporating this spring is used in a place with severe environmental conditions such as outer space, it is possible to prevent the device from becoming inoperable due to lateral deformation.

[Brief description of the drawings]

FIG. 1 is a vertical cross section of a cylindrical coil according to a first embodiment.

FIG. 2 is a spring characteristic diagram of the cylindrical coil of the first embodiment.

FIG. 3 is a side view of a cylindrical coil according to a second embodiment.

[Explanation of Codes] 1 Cylindrical coil 2 Elementary wire d1 Elemental diameter of central part d2 Elemental diameter of both ends p1 Pitch of central part p2 Pitch of both ends

Claims (2)

[Claims] 1. A coil spring for preventing lateral deformation, which is a cylindrical coil spring having a central wire cross-sectional area smaller than both end wire cross-sectional areas. 2. A coil spring for preventing lateral deformation, wherein the coil pitch of the central portion of the cylindrical coil spring is smaller than the coil pitch of both ends.